Perpendicular magnetic recording has been developed in part to achieve higher recording density than is realized with longitudinal recording devices. A PMR write head typically has a main pole layer with a small surface area at an air bearing surface (ABS), and coils that conduct a current and generate a magnetic flux in the main pole such that the magnetic flux exits through a write pole tip and enters a magnetic medium (disk) adjacent to the ABS. Magnetic flux is used to write a selected number of bits in the magnetic medium and typically returns to the main pole through two pathways including a trailing loop comprised of a trailing shield structure, and a leading loop comprised of a leading shield and back gap connection. The double write shield (DWS) design that features the leading and trailing loops was invented for adjacent track erasure (ATE) improvement by reducing stray field in side shields and in the leading shield. A PMR writer has a great advantage over longitudinal magnetic recording (LMR) in providing higher write field, better read back signal, and potentially much higher areal density.
Perpendicular magnetic recording has become the mainstream technology for disk drive applications beyond 150 Gbit/in2. With the growing demand for cloud storage and cloud-based network computing, high and ultra high data rate recording becomes important for high-end disk drive applications. Thus, it is essential to design a PMR writer that can achieve high area density capability (ADC) in addition to improved stray field robustness characterized by low ATE and a bit error rate (BER) of about 10−6 or less.
In today's PMR heads, the critical dimensions (CDs) of the PMR writer such as the track width (TW) are within a 10 nm to 100 nm range. However, the capabilities of process tools and variations in writer CDs have not been keeping up with the reductions in CDs. As a result, there are typically large fluctuations in writer performance, which impact both HGA yield and subsequent HDD yield. Thus, there is a need for an improved PMR writer design that minimizes variations in writer performance, and a means of integrating the design that comprises multiple writer pads with a plurality of trace lines which form electrical connections from a preamp in the HGA to the writer structure on a slider.